How can I get inside North Korea?

Vice's Shane Smith entered North Korea through Shenyang, China

you need approved documents from officials in your country and from NK

They let you in mostly during the Arirang Games

Start small and read about the country first, then go there as a tourist. As long as you aren't a journalist or a professional photographer, you can.

Of course on an organized tour, you will not see the everyday life of people there. You will be shown the very best the country has to offer, and you will be in the company of at least two North Korean tour guides at all times. We had three guides, a bus driver of course, and there also was a camera man who filmed everything we did. This was for a group of 15 people. ... Your tour guides will watch you closely, for instance one of ours once told me, "oh, you didn't take photos from the bus yesterday night". And they are smart. Of course they realize that you aren't going to believe everything you are told, but as long as you don't actually say so, both you and your guides are going to be fine.

If this sounds somewhat contrived, well that's how it is. When in North Korea, you always have to think about what you are doing because everything matters. (I remember the bee. When we were leaving by train, there suddenly was a bee in our compartment. Of course we didn't want it there. It was sitting on my sleeve, so one of the others opened the window in the corridor for me, and I tried to shake it off. It wouldn't let go. And within seconds, someone in uniform came and rudely asked what we were doing. I showed him the bee, which was still sitting on my sleeve. But now, it flew off and sat down next to the window. The man in uniform took it by the wing, threw it out and banged the window shut. Then he turned around and left without another word. ... That's how important little things are.)

There are only very limited opportunities to actually live in North Korea for an extended period of time. Maybe you could go as an English teacher, if you have the necessary qualifications and if they need an English teacher at the moment. There are only a handful of other foreigners living in Pyongyang (around 150 afak). One of them has a pizza place, another one a DHL agency. But this is Pyongyang. The life of people elsewhere in the country is different.

So I'd go there as a tourist and read the books of those who have lived in the DPRK for a longer time.

Of course you can, they want tourist. So make sure you can afford few thousands a year. And don't talk about democracy etc. since they will arrest you.